Explosion-alleviator for internal-combustion engines



B. BANNISTER.

EXPLOSION ALLEVIATR FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED JULY 26, i920. I

INVENTOR lll) illt

BRYANT BANNISTER, OF PITTSBURGH, PENNSYLVANIA.

EXPLOSION-ALLEVIATOR FOR INTERNALi-COMBUSTION ENGINES. m n

Specification o Letters iatent.

Patented Nov. 23, 1920.

Original application filed February 25, 1920, Serial No. 361,225.` Divided and this application lled July 26,1920. Serial No. 399,127. i

f1 7o ad fw hom 'it may cof/cern .lle it known that l, BRYANT BANN'isrEn, a citizen of the United States, and resident oi' ittsburgh, in the county of rillegheny and t' late of Pennsylvania, have invented a new and useful Improvement in 'Explosion iillevialors .tor Internal-Combustion En ginas, ol" which the following is a specifi cation. y

This invention relates to an explosion allek viator for internal combustion engines, and

a division oi' copending application, Serial No. 361,225, filed February 945, 1920.

`Une object ol the ilfivention is to provide mechanism 'for use in conjunction with in ternal combustion engines, which renders possible the employment of a high compression without the occurrencewithin the cyl-` inder of a correspondingly high explosion pressure at any instant.

Another object of the inventionis to provide means which smooth out the high preesure impulse incident to the explosion of the combustible charge, over an increased portion of the power stroke of the engine piston; thus not only damping the sharp initial rise in pressure during combustion ol't the charge, but also preventing the usual abrupt drop in pressure during expansion. l

A further object of the invention is to provide valve means which serve to secure the hull effect of the pressure alleviation and conservation by operating with suflicient speed after ignition of the combustible charge to permit expansion into an aux iliary clearance space during the progress of combustion. y Y

il practical advantage derived from` the foregoing is that `internal combustion en gines may be readily modified so as to materially increase compression, and secure a substantial gain in available power and in economy, without greater' stress in, or shocl to, the engine parts. Thus by decreasing the clearance space within the cylinder, or cylinders, of the engine, "orby increasing the piston displacement without increasing the volume of the clearance space, a compression ratio oifour to one and greater may be obtained without increasing the strength of the cylinder head, cylinder walls, or moving parts. y p

Further practical advantages derived lrom use ci' the device, are increased power andtorqua` and increased flexibility of operation.

lt is, ol'- course, possible to allow' the coinpression ratio to remain as before and to secure economy in manufacture by" lessening the amount of metal in the cylinder, 0r c vlinders, of the engine to which the device is applied.

In the accompanying drawings Figure l is a vertical. sectional view of the explosion alleviator; `Fig. 2 is a View of the valve units connected to a common auxiliary clearance chamber, one unit being shown in plan and the other being shown in horizontal section;

and Fig. 3 is a vertical sectional view show ing the explosion alleviator on a reduce-:l scale and illustrating operating connections tor the valve means of the alleviator.

The device of the present invention is shown in conjunction with the cylinder, or cylinders, oll an internal combustion engine; and is arranged to communicate with the clearance space of such cylinder or cylinders. lVith reference particularly to Fig. l. of the drawings, the numeral l designates an auX- iliary clearance,` or expansion, chamber which communicates with the interior ofthe cylinder `by way of a passage 2. Control ling passage 2 from the cylinder clearance is a valve 3 having a seat l within the passage.

The specific functional idea `or the explosion alleviator is to open communication be tween the clearance spacein the cylinder' and thev auxiliary clearance shortly after ignition and before combustion is complete, thereby permitting the combustion products to expand into the auxiliary clearance and damp the initial explosive force following upon ignition; to maintain the 'valve open throughout a portion of the power stroke so that pressure built up in the auxiliary clearance may operate upon the cylinder piston during a portion of the expansion stroke therein;` and to maintain the valve controlling communication between the cylinder clearance and the` auxiliary clearance closed during the latter part of the expansion stroke and `during the exhaust, intake, and compression strokes, so ythat `the space into which the combustible charge is compressed is no greater than is normal with the cylinder itself.

. municated to a combustible charge within` It is necessary, in order to obtain a smooth distribution of explosive force, that the valve should be maintained in its open position during a sufficient portion of the power stroke to permit pressure, which has been vbuilt up inthe auxiliary clearance during seat within a few teny thousandths of a second following the instant of ignition.

It is also necessary that the valve be returned to its seat promptly when the pressure within the auxiliary clearance has performed its function, and that it remain closed duringthe compression stroke in the cylinder. Otherwise ignition would be comthe auxiliary clearance upon ignition of the chargein the engine cylinder. Y

The valve 3 is provided with a valve stem 5, preferably provided at its lower extremity with a roller 6. Against the lower extremity of valve stem 5 bears a cam 7 on a cam shaft 8.

' 'The cam shaft 8 may be actuated by any suitable connection with the crank shaft of Vthe engine to which the device is applied, or

byany other suitable timed actuating means.

It will be understood that thecam must be designed and the timing be such that the valve is lifted substantially instantaneously upon ignition'in the engine cylinder. The design of the cam is such that it will maintain the valve open during the desired portion of the power stroke in the cylinder.

Y Against a suitable collar 9on valve stem 5 bears a helical spring 10, which exerts a force tending to maintain the valve in seated position. When the high, or inoperative, portion of the campasses out of contact .with the lower extremity of the valve-stem, the spring l0 serves to return the valve promptly toits seat. Obviously, spring l() must be of suiiicient strength to maintain the valve 3 1n seated position during the comvlpression y stroke in the engine cylinder.

Fig.` 3 of the drawings illustrates convenient means'for operating Vthe cam shaft 8, Vwhich carries the cam .7 for producing the timed lifting of the valve 3. Such means comprise a gear l2 on cam shaft 8 and meshvlng with a gear 1 3 on the main cam shaft of the engine. `Obviously the operation ,of the cam shaft 8 may be secured by various actuating means and connections adapted to varying forms of internal combustion engine in conjunction with which the alleviator is employed.`

The auxiliary clearance chamber is preicrably provided with a heat insulating lining ll, so that loss of heat. dne te this increased radiating surface, is miniinizced. .\s shown in Fig. 2 of the dranf'ings, the auxiliary clearance chamber is preferably made common to all the cylinders of an engine. when the engine to which the device is applied is of the multi-cylinder type. ln .sin-'n case, the auxiliary clearancel has a valve een trolled communication with the clearance space of each of the cylinders.

lVhen the cam functions, liftinn'tlie valve after ignition in the engine cylinder. gases expand into the auxiliary clearance, further compressing` any gas trapped in the auxiliary clearance upon previous closing` of the valve. As the pressure within the cylinder drops duringthe power stroke in the cylinder, this pressure within the auxiliary elen ance acts upon the piston in the cylinder lo do work thereon, the valve remaining lifted during this interval. Spring l0 causes the valve to be resented when the cam ceases to exert a positive upward pressure upon the valve stem. rThe timed relation between the cam shaft and moving parts of the engine must be such that the valve remains seated until after the ignition of the succeeding charge in the engine cylinder.

A number of modifications may be made in the form and arrangement of the auxiliary clearance and controlling valve, und also in the valve operating means and their connections without departing from the spirit of the invention. The scope of the invention is therefore to be restricted only to the limitations contained in the appended claims.

lVhat I claim is:

-1. ln conjunction with an internal combustion engine an auxiliary clearance chamber in communication with the clearance space of a` cylinder. normally seated valve means controlling such communication. and means actuated by the moving parts of the engine arranged to unseat the valve. after ignition in the engine cylinder and to maintain said valve unseated during a portion ofthe power stroke in the cylinder.

2. ln conjunction with an internal combustion engine an auxiliary clearance chamber in communication with the clearance space of a cylinder. normally seated valve means controlling such communication, and mechanically operated means arranged to unseat the valve after ignition in the engine cylinder and to maintain said valve unseated during a portion of the power' stroke in the cylinder.

3. In conjunction with an internal combustion engine an auxiliary clearance chamill ber in communication with the clearance space of a cylinder, normally seated Valve means controlling such communication, a cam arranged to act upon the valve means, and connections with the moving parts of the engine whereby said cam is caused to lift the valve after ignition in the engine cylinder and to maintain it unseated during a portion of the power stroke in the cylinder. n

4t. In conjunction with an internal combustion engine an auxiliary clearance chamber in communication with the clearance space or' a cylinder, valve means controlling such communication, means actuated by the moving parts of the engine arranged to unseat the valve after ignition in the engine cylinder and to maintain said valve unseated during a portion of the power stroke in `the cylinder, and resilient means arranged to exert a force greater than that caused by compression in the engine cylinder for normally maintaining said valve seated.

5. In conjunction with an internal combustion engine an auxiliary clearance chamber in Communication with the clearance space of a cylinder, valve means controllin such communication, mechanically operatecgl means arranged to unseat the valve after ignition in the engine cylinder and to maintain said valve unseated during a portion of the power stroke in lthe cylinder, and resilient means arranged to exert a force greater than that caused by compression in the engine cylinder for normally maintaining said valve seated. i

46. In conjunction with an internal combustion engine an auxiliary clearance chamber in communication with the clearance space of acylinder, valve means controlling such communication, a cam arranged to act upon saidvalve means, connections with the moving parts of the engine whereby said cam is caused to lift the valve after igni tion in the engine cylinder andto maintain it unseated during a portion of the power stroke in the cylinder, and resilient means arranged to exert a force greater than that caused by compression in the engine cylin der for normally maintaining said valve seated.

In witness whereof, `I hereunto set my hand. i

n BRYANT BANNISTER.

Witnesses:

FLORENCE F. SCHWARTZ, Guerra W. ALsroN. 

